P0439 OBD II Trouble Code Catalyst Heater Control Circuit Bank 2

Symptoms of P0439 OBD II Trouble Code

  • Decreased fuel efficiency
  • A lack of general engine performance
  • Excessive black smoke from exhaust
  • Other related diagnostic trouble codes
  • MIL (malfunction indicator lamp) illumination

Common Causes of P0439 OBD II Trouble Code

  • Defective exhaust temperature sensor
  • Improper or insufficient diesel exhaust fluid
  • Malfunctioning diesel exhaust fluid injection system
  • Burnt, chafed, broken, or disconnected wiring and/or connectors
  • Faulty O2 sensor/s
  • Bad catalytic converter
  • Engine exhaust leak

Severity of P0439 OBD II Trouble Code

Since the catalyst heater is crucial for exhaust emission reduction, a code P0439 should be considered severe.